Disease Modifier These article contains a recent description of disease modifiers for SCD: http://www.nejm.org/doi/10.1056/NEJMra1510865 -- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4562292/ -- -- Paper mentioning haplotypes and severity: -- https://www.nature.com/scitable/topicpage/sickle-cell-anemia-a-look-at-global-8756219 -- -- Initially, the HP term "Clinical Modifier" (HP:0012823) was used to define this class, but its usage was found to be more "ontology-based" than what the SCDO intended. None SCDO (Jade Hotchkiss) A factor that modifies one or more aspects of a disease, such as sickle cell disease (SCD) (e.g. aspects such as temporal pattern, age of onset and mortality), for specific phenotype(s) of the disease. Phenotypic Modifier Request inclusion into relevant ontology SCDO